Kim Do Hyeon, Lee Gil Ju, Heo Se-Yeon, Son Soomin, Kang Kyeong Muk, Lee Heon, Song Young Min
Opt Express. 2021 Sep 27;29(20):31364-31375. doi: 10.1364/OE.438662.
For the efficient radiative cooling of objects, coolers should emit heat within atmospheric transparent window and block heat absorption from the surrounding environments. Thus, selective emitters enable highly efficient cooling via engineered photonic structures such as metamaterials and multi-stacking structures. However, these structures require sophisticated fabrication processes and large quantities of materials, which can restrict mass-production. This study introduces an ultra-thin (∼1 μm) and near-unity selective emitter (UNSE) within the atmospheric window, which can be fabricated using simple and affordable process. The combination of infrared (IR) lossy layers and high index lossless layer enhances the resonance in the structure thus, the emissivity in long wavelength IR region increases to near-unity within a thickness of ∼1 μm.
为了实现物体的高效辐射冷却，冷却器应在大气透明窗口内散热，并阻止周围环境的热量吸收。因此，选择性发射体能够通过超材料和多层堆叠结构等工程光子结构实现高效冷却。然而，这些结构需要复杂的制造工艺和大量材料，这可能会限制大规模生产。本研究介绍了一种在大气窗口内的超薄（约1μm）且接近全发射率的选择性发射体（UNSE），它可以通过简单且经济的工艺制造。红外（IR）损耗层和高折射率无损层的组合增强了结构中的共振，因此，在约1μm的厚度内，长波长红外区域的发射率增加到接近全发射率。
